Wearable devices (WDs) are a key market for Internet of Things (IoT). Examples WDs include smart watches, activity trackers, personal health monitors, sports cameras, augmented reality (AR) gadgets, and so on. In order to realize their full potential as IoT devices, the WDs need to be connected to the Internet, at least on an intermittent basis.
Due to their small form factor and the fact that they move when a user wearing them moves, WDs usually run on battery power. In order to prolong the life of the battery, WDs usually do not directly connect to a public land mobile network (PLMN) that uses a cellular technology, because that typically consumes a lot of power. Instead, WDs usually connect to the Internet via a hub device such as a smartphone, for example, when the user is on the move, or a short-range radio device plugged in the power line or an access point (AP) co-located with a home gateway, for example, when the user is at home, wherein the hub device is connected to the Internet using cellular, short-range radio, and/or wire-line technology. The hub device usually operates on utility power or has a larger battery than the ones in WDs. WDs are connected to the hub device using a short range radio technology, such as IEEE 802.11/Wi-Fi, Bluetooth Low Energy (BLE), IEEE 802.15.4/ZigBee, and so forth. Because IEEE 802.11 communications systems (also commonly referred to as Wi-Fi communications systems) are ubiquitous in residences, enterprises, public places, and consumer electronics, Wi-Fi may also become dominant in the WD market if the power consumption of Wi-Fi can be reduced to be on par with BLE or ZigBee.